Bug 1046003 - Ensure duplicate frames after a seek have an Image. r=kinetik

content/media/MediaData.cpp

@@ -158,6 +158,22 @@ VideoData* VideoData::ShallowCopyUpdateTimestamp(VideoData* aOther,
   return v;
 }
 
+/* static */
+VideoData* VideoData::ShallowCopyUpdateTimestampAndDuration(VideoData* aOther,
+                                                            int64_t aTimestamp,
+                                                            int64_t aDuration)
+{
+  NS_ENSURE_TRUE(aOther, nullptr);
+  VideoData* v = new VideoData(aOther->mOffset,
+                               aTimestamp,
+                               aDuration,
+                               aOther->mKeyframe,
+                               aOther->mTimecode,
+                               aOther->mDisplay);
+  v->mImage = aOther->mImage;
+  return v;
+}
+
 /* static */
 void VideoData::SetVideoDataToImage(PlanarYCbCrImage* aVideoImage,
                                     VideoInfo& aInfo,

content/media/MediaData.h

@@ -209,6 +209,13 @@ public:
   static VideoData* ShallowCopyUpdateTimestamp(VideoData* aOther,
                                                int64_t aTimestamp);
 
+  // Creates a new VideoData identical to aOther, but with a different
+  // specified timestamp and duration. All data from aOther is copied
+  // into the new VideoData, as ShallowCopyUpdateDuration() does.
+  static VideoData* ShallowCopyUpdateTimestampAndDuration(VideoData* aOther,
+                                                          int64_t aTimestamp,
+                                                          int64_t aDuration);
+
   // Initialize PlanarYCbCrImage. Only When aCopyData is true,
   // video data is copied to PlanarYCbCrImage.
   static void SetVideoDataToImage(PlanarYCbCrImage* aVideoImage,

content/media/MediaDecoderStateMachine.cpp

@@ -2690,9 +2690,28 @@ nsresult
 MediaDecoderStateMachine::DropVideoUpToSeekTarget(VideoData* aSample)
 {
   nsAutoPtr<VideoData> video(aSample);
-
+  MOZ_ASSERT(video);
+  DECODER_LOG(PR_LOG_DEBUG,
+              "DropVideoUpToSeekTarget() frame [%lld, %lld] dup=%d",
+              video->mTime, video->GetEndTime(), video->mDuplicate);
   const int64_t target = mCurrentSeekTarget.mTime;
 
+  // Duplicate handling: if we're dropping frames up the seek target, we must
+  // be wary of Theora duplicate frames. They don't have an image, so if the
+  // target frame is in a run of duplicates, we won't have an image to draw
+  // after the seek. So store the last frame encountered while dropping, and
+  // copy its Image forward onto duplicate frames, so that every frame has
+  // an Image.
+  if (video->mDuplicate &&
+      mFirstVideoFrameAfterSeek &&
+      !mFirstVideoFrameAfterSeek->mDuplicate) {
+    VideoData* temp =
+      VideoData::ShallowCopyUpdateTimestampAndDuration(mFirstVideoFrameAfterSeek,
+                                                       video->mTime,
+                                                       video->mDuration);
+    video = temp;
+  }
+
   // If the frame end time is less than the seek target, we won't want
   // to display this frame after the seek, so discard it.
   if (target >= video->GetEndTime()) {